/* 
 * [New BSD License (BSD 3-Clause License)]
 * Copyright (c) 2012, Max Bechtold
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     - Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     - Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     - Neither the name of the Rel2Xml Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package maxbe.rel2xml.generator.dml.predicates;

import maxbe.rel2xml.generator.dml.ResultColumn;

/**
 * Represents a comparison between two columns' values
 * 
 * @author Max Bechtold
 * 
 */
public class ColumnComparison implements Predicate {

	private final ResultColumn column1;
	private final ResultColumn column2;

	private final Comparison comparison;

	/**
	 * If a join predicate is already explicit through the table mapping, this
	 * Predicate is implicit and will be ommitted in the respective XQuery
	 */
	private boolean omit;

	public ColumnComparison(ResultColumn column1, ResultColumn column2,
			Comparison comparison) {
		this.column1 = column1;
		this.column2 = column2;
		this.comparison = comparison;
	}

	public ResultColumn getColumn1() {
		return column1;
	}

	public ResultColumn getColumn2() {
		return column2;
	}

	public Comparison getComparison() {
		return comparison;
	}

	public boolean isOmit() {
		return omit;
	}

	public void setOmit(boolean omit) {
		this.omit = omit;
	}

	@Override
	public String toXQuery() {
		return toXQuery(false);
	}

	@Override
	public String toXQuery(boolean omitAliases) {
		if (omitAliases)
			return String.format("%s %s %s", column1.getXmlName(),
					comparison.getOperator(), column2.getXmlName());
		else
			return String.format("$%s/%s %s $%s/%s", column1.getEntity()
					.getAlias(), column1.getXmlName(),
					comparison.getOperator(), column2.getEntity().getAlias(),
					column2.getXmlName());
	}

	@Override
	public String toSql() {
		return toXQuery();
	}

	@Override
	public String toString() {
		return toSql();
	}

}
